• Visitors can check out the Forum FAQ by clicking this link. You have to register before you can post: click the REGISTER link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. View our Forum Privacy Policy.
  • Want to receive the latest contracting news and advice straight to your inbox? Sign up to the ContractorUK newsletter here. Every sign up will also be entered into a draw to WIN £100 Amazon vouchers!

Fixing a hi-fi

Collapse
X
  •  
  • Filter
  • Time
  • Show
Clear All
new posts

    Fixing a hi-fi

    Have a oldish, reasonable Hifi, as separates... actually only using the core amp now. It has developed an odd fault that when you turn it on no sound comes out. If you start it playing something then a few minutes later you get a very quiet level appearing from one or both speakers, which gradually (or in little jumps sometimes) increases to where it should be based on the volume.

    I initially thought it was just broken or the speaker cables were to blame, but swapping the speakers round and jiggling them shows it's totally consistent, no intermittent connections there. Similarly, the volume knob doesn't act erratic.

    This weird "warming up" behaviour, what could it be? Why would a modern bit of kit do this, not like it's got valves?! Loose connection maybe inside, or a dry joint?
    The system was acting as our TV external audio but has been relegated as my PC sound now due to the problems. I can't really justify to myself buying proper hi-fi separates for my PC but if I can get it working it's SO much nicer than crummy computer speakers, and then I can buy something new for the TV.
    Originally posted by MaryPoppins
    I'd still not breastfeed a nazi
    Originally posted by vetran
    Urine is quite nourishing

    #2
    Originally posted by d000hg View Post
    Have a oldish, reasonable Hifi, as separates... actually only using the core amp now. It has developed an odd fault that when you turn it on no sound comes out. If you start it playing something then a few minutes later you get a very quiet level appearing from one or both speakers, which gradually (or in little jumps sometimes) increases to where it should be based on the volume.

    I initially thought it was just broken or the speaker cables were to blame, but swapping the speakers round and jiggling them shows it's totally consistent, no intermittent connections there. Similarly, the volume knob doesn't act erratic.

    This weird "warming up" behaviour, what could it be? Why would a modern bit of kit do this, not like it's got valves?! Loose connection maybe inside, or a dry joint?
    The system was acting as our TV external audio but has been relegated as my PC sound now due to the problems. I can't really justify to myself buying proper hi-fi separates for my PC but if I can get it working it's SO much nicer than crummy computer speakers, and then I can buy something new for the TV.
    Look for bulging or leaking capacitors (the cylinder shaped things) they should be flat on top, easy to source and replace.
    Science isn't about why, it's about why not. You ask: why is so much of our science dangerous? I say: why not marry safe science if you love it so much. In fact, why not invent a special safety door that won't hit you in the butt on the way out, because you are fired. - Cave Johnson

    Comment


      #3
      Originally posted by d000hg View Post
      This weird "warming up" behaviour, what could it be? Why would a modern bit of kit do this, not like it's got valves?! Loose connection maybe inside, or a dry joint?
      It will be a broken solder joint somewhere. Thermal expansion will fix it whilst it's hot!
      Coffee's for closers

      Comment


        #4
        Originally posted by Spacecadet View Post
        It will be a broken solder joint somewhere. Thermal expansion will fix it whilst it's hot!
        You will need.
        PCB Cleaner.
        Flux Pen
        Soldering Iron
        Soft solder

        Take out the PCBs and clean them.
        Use the flux pen to wet every solder joint and gently touch each joint with the hot iron so that the solder flows. If needed add some solder. It has probably failed on one of the components that gets hot.
        "A people that elect corrupt politicians, imposters, thieves and traitors are not victims, but accomplices," George Orwell

        Comment


          #5
          Originally posted by Paddy View Post
          You will need.
          PCB Cleaner.
          Flux Pen
          Soldering Iron
          Soft solder

          Take out the PCBs and clean them.
          Use the flux pen to wet every solder joint and gently touch each joint with the hot iron so that the solder flows. If needed add some solder. It has probably failed on one of the components that gets hot.
          Or buy a new amp
          Coffee's for closers

          Comment


            #6
            Shame to buy one for £100 if 10min might find something obvious.
            Originally posted by MaryPoppins
            I'd still not breastfeed a nazi
            Originally posted by vetran
            Urine is quite nourishing

            Comment


              #7
              Originally posted by Spacecadet View Post
              Or buy a new amp
              Indeed. I love second hand hi-fi bargains. I bought myself a jolly nice Marantz number a couple of Christmas ago when I made a few bob from a sideline. I think it was something like £2500 new and I got it for £420. Magic amp. Then again, getting your current one fixed shouldn't be too hard and a bit cheaper.

              Comment


                #8
                Originally posted by Spacecadet View Post
                Or buy a new amp
                Cleaner £6
                Flux £7
                Solder £3
                Iron £20

                Yes; buy a new amp on eBay!
                "A people that elect corrupt politicians, imposters, thieves and traitors are not victims, but accomplices," George Orwell

                Comment


                  #9
                  Hadn't thought about 2nd hand, though I don't really like buying heavy things on eBay. But tools and so on I have or could borrow, the only cost is my time so a few minutes is ok, but much more and it's cheaper to just buy.

                  If I open the amp up, how long after turning it off should I wait? Is it useful to do it while still warm, or should one wait several minutes to avoid charged capacitors?
                  Originally posted by MaryPoppins
                  I'd still not breastfeed a nazi
                  Originally posted by vetran
                  Urine is quite nourishing

                  Comment

                  Working...
                  X